Bulked yarn



3,473,316 I BULKED YARN Donald Glyn Jenkins, Ahersychan, and Anil Chandral-rant larilrh, Caerleon, England, assignors to British Nylon Spinners Limited, Pontypool, Monmouthshire, England No Drawing. Filed Nov. 18, 1964, Ser. No. 412,248 filaims priority, application Great Britain, Nov. 19, 1963,

45,546/63; Jane 3, 1964, 22,931/64 Int. Cl. D02g 3/02; D0411 17/00; D05c /00 US. Cl. 57-140 3 Claims ABSTRACT OF THE DISCLOSURE A bulked yarn is manufactured by drawing undrawn yarn and immediately bulking the drawn yarn in a stufferbox crimper. The yarn is forwarded to the crimper at an overfeed. The crimps are set in the yarn in the setting chamber of the crimper, after which the yarn is wound The invention concerns improvements in or relating to bulked yarn.

In this specification the term yarn is to be regarded as covering all continuous yarn-like structures containing a plurality of filaments, whatever the total denier thereof. Hence, the expression includes continuous filamentary tow of a denier suitable for yarn manufacture but not that for the manufacture of a staple fibre in bulk.

Bulked yarns are made by crimping, and by other such means having the effect of disarranging the filaments to cause them to adopt irregular, rather than parallel, paths.

Of the various bulked yarns that are in commercial use, one such yarn which is used to a considerable extent in textile articles of all kinds, including articles of underclothing and outer clothing and carpets, is one whose filaments have a crimp of a generally saw-tooth nature. The usual way in which such a bulked yarn is made is by stuffer-box crimping.

A bulked yarn of the above-described type is useful for many textile purposes, but we have appreciated that there is a need for a bulked yarn having a greater bulk and a higher uniformity of crimp frequency than those presently possessed by yarns of that type, particularly heavy denier bulked yarn destined for use in carpets of the cutpile tufed variety. In such like uses, any non-uniformity of crimp frequency may show up as streakiness in the dyed fabric; and high bulk is desirable in order, for instance, to provide a dense pile. Streakiness results from the difference in lustre of fibres having different degrees of crimping therein, and from the fact that a highlycrimped fibre will retract to a greater extent than a lowlycrimped one On being subjected to heat, e.g. during dyeing of a cut-pile carpet fabric.

The main object of this invention is therefore the provision of a bulked yarn having certain defined characteristics making it useful in a wider range of textile articles than is presently possible.

According to the invention, a bulked yarn of synthetic thermoplastic material, suitable for use in e.g. cut-pile tufted carpets without visible lustre differences being discernible therein, consists of a yarn (as hereinbefore defined) with crimps in each of the filaments thereof, and having the following characteristics:

(a) a crimp frequency in all the filaments of greater than about 8 crimps per inch,

(b) a range of crimp frequency measured along any filament of less than about 15% above and below the mean crimp frequency,

(c) a skein length (as hereinafter defined) of less than about 18 inches, and

ited States Patent 0 (d) an equivalent steam setting temperature (E.S.S.T.)

(as hereinafter defined) of at least about C.

Preferably, such a yarn has crimps of a generally sawtooth nature in the filaments thereof; but the regularity or irregularity of the form of such crimps will depend on the use for which the yarn is required. An irregular form of crimp, with the crimps in different planes and out of phase between filaments, is often desirable, particularly in carpet pile yarns.

The above-mentioned crimp frequency is measured on yarn withdrawn from a package and first treated for /2 hour in atmospheric steam under conditions of nil loading to develop the crimp. At least 8 crimps per inch are required to denote the necessary bulk; and preferably the frequency is between 15 and 25 crimps per inch.

The skein length, which is a measure of the yarn bulk, is determined as follows, the figures quoted being relevant to the testing of yarn of 3,500 denier: a 15-metre skein (having 15 one-metre wraps) is Wound on a wrap reel, the yarn being lightly tensioned during winding by passing it through an angle of 90 around a tensioning rod. A weight of 60 grams is placed on the skein whilst on the reel, and a suspension hook is placed on the skein opposite to the loading weight and the skein then removed from the reel. The skein is then lowered into a glass tube containing water maintained at 60 C., and its skein length measured after a period of 2 minutes total immersion. The shorter the skein length, the greater the bulking power of the yarn; and such thoroughly-contracted yarns are useful in e.g. felts for tennis ball covers or for industrial processes.

The equivalent steam setting temperature (E.S.S.T.) above referred to is measured in accordance with the procedure set-out in the Hosiery and Allied Trades Research Association (H.A.T.R.A.) Research Report No. 7 of February 1958, by D. L. Munden and D. Slater, entitled A quality control test for normal, bulked and stretch nylon yarns. In such test, the shrinkage of the yarn specimen in pressure steam at C. is measured, and the result expressed as a setting temperature (in steam) that is known to produce a yarn with an equivalent shrinkage. Hence, the higher the E.S.S.T., the more wholly is the yarn set, and the less affected will the yarn be by such after-processes as dyeing and space-dyeing.

One such bulked yarn according to the invention can be made by a drawing and bulking process described in the specification of our copending application Ser. No. 411,966, filed on even date herewith, now US. Patent No. 3,341,913. According to one embodiment of that process, undrawn nylon yarn is drawn and then immediately for warded, at a low degree of mechanical overfeed, to a stuffer-box apparatus in which the freshly-drawn yarn is bulked.

An example of such a process and of the yarn so produced is as follows:

Three singles yarns (ends) of undrawn 3600 denier/ 68 filament nylon 66 yarn, as spun, were drawn at a draw ratio of 3.7:1 and then immediately bulked in a stufferbox crimper, being forwarded thereto at a mechanical overfeed of 7 /2 The bulked yarn was set in the setting chamber of the crimper and then wound up.

With a load of 1 lb. applied to the compressed yarn in the crimping chamber, a skein length of 15 /2 inches was obtained in the bulked yarn, which was suitable for carpet pile yarn; with a load of 3 lbs. applied, a skein length of 13 inches was obtained, and the yarn was suitable for felt manufacture. It is to be noted that such a short skein length, indicative of great bulking power, is not obtainable by stuffer-box crimping drawn nylon supply yarns of comparable denier in the drawn state, whatever the crimping load applied.

The crimp frequency of the yarn was 20 per inch, with a range of i2 crimps per inch along any filament. This compared with a range of i8 crimps per inch, for an equivalent mean value, obtained when the supply yarns were drawn nylon yarns.

The equivalent steam setting temperature (E.S.S.T.) was 110 C. This value compared with one of 87 obtained when the supply yarns were drawn nylon yarns and the crirnper rolls were maintained at the same temperature; or one of 101 C. obtained with such drawn yarns but with the crimper rolls at a temperature some 30 C. higher owing to a much greater crimping load having been applied to achieve an equivalent skein length.

Thus, the bulked yarn so produced was one which had a greater uniformity of crimp frequency along the filaments, an equivalent or greater bulking capacity, and a higher E.S.S.T. than one produced according to the known processes.

It is the combination of these improved properties in a bulked yarn which enables it to be used in textile manufactures where heretofore 'bulked continuous filament yarn has not been able to be used.

The often-desirable, irregular form of crimp is obtainable With relatively high overfeeds, in the range 3%- 9%, and relatively low loads, say of 1 lb.2 1b. in amount.

Although the above example of a bulked yarn refers to nylon 66 (polyhexamethylene adipamide), such a yarn is also capable of being made of other types of nylon, such as nylon 6 (polycaprolactam), and of polyester and polypropylene materials.

What we claim is:

1. Bulked continuous filament yarn consisting of a plurality of filaments of a synthetic thermoplastic material, each of the filaments having crimps therealong, and the yarn being characterised in that:

(a) the crimp in each of the filaments is of a frequency greater than 8 crimps per inch,

(b) the range of crimp frequency measured along any filament is less than 15% above and below the mean crimp frequency,

(0) it has a skein length of less than 18 inches, and

(d) it has an equivalent steam setting temperature (E.S.S.T.) of at least C.

2. Bulked continuous filament yarn according to claim 1 in which the crimps are of generally saw-tooth nature but irregular in form with the crimps is different planes and out of phase between filaments.

3. Bulked continuous filament yarn according to claim 1 in which the crimp frequency is between 15 and 25 crimps per inch and the skein length is between 13 and 15 /2 inches.

References Cited UNITED STATES PATENTS 3,376,622 4/1968 Stanley 2872 3,145,947 8/1964 Stanley 2872 X 3,177,556 4/1965 Van Blerk 28-72 3,234,626 2/1966 Faria 28-l JOHN PETRAKES, Primary Examiner US. Cl. X.R.

WW UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,473,316 Dated October 21, 1969 Inventor(s) Donald Glyn Jenkins and Anil Chandrakant Parikh In column 2, line 14, "denote" should be --donate---.

In column 2, line 49 "411,966" should be ---4ll,996---.

In column 4, claim 2, line 3, "is" should be --in---.

Signed and sealed this 9th day of May 1972.

(SEAL) Attest:

EDWARD I-T.FLETCHE;R,JR. ROBERT GOTTSCHALK Abtesting Offi er Commissioner of Patents 

